EGR Valve - Miata

Resistance Inspection

Disconnect EGR valve 6-pin harness connector. See Figure. Using an ohmmeter, measure resistance between EGR valve terminals "C" and "E", "C" and "A", "D" and "B" and between "D" and "F". See EGR VALVE RESISTANCE SPECIFICATIONS table. If resistance is as specified, check for open or short circuit. Go to next step. If resistance is not as specified, replace EGR valve.

Open Circuit Inspection

Disconnect PCM 17-pin harness connector. Check for continuity between following terminals:
- EGR valve 6-pin harness connector terminal "E" and PCM 17-pin harness connector terminal No. 2E (Light Green wire).
- EGR valve 6-pin harness connector terminal "A" and PCM 17-pin harness connector terminal No. 2F (White/Green wire).
- EGR valve 6-pin harness connector terminal "B" and PCM 17-pin harness connector terminal No. 2H (Pink/Black wire).
- EGR valve 6-pin harness connector terminal "F" and PCM 17-pin harness connector terminal No. 2I (Pink wire).
- EGR valve 6-pin harness connector terminal "C" or "D" and main relay 4-pin harness connector terminal "C" (White/Red wire).
If continuity is present, go to next step. If continuity is not present, repair open circuit in suspect wire or replace wire harness. See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS.

Short Circuit Inspection

Check for continuity between following:
- EGR valve 6-pin harness connector terminal "E" (Light Green wire) and ground.
- EGR valve 6-pin harness connector terminal "A" (White/Green wire) and ground.
- EGR valve 6-pin harness connector terminal "B" (Pink/Black wire) and ground.
- EGR valve 6-pin harness connector terminal "F" (Pink wire) and ground.
- EGR valve 6-pin harness connector terminal "C" or "D" (White/Red wire) and power supply.
If continuity is present, repair short circuit in suspect wire or replace wire harness. If no open or short circuit is present, remove EGR valve and inspect for any damage or clogging. If there is no damage or clogging, replace EGR valve.